Internal combustion engines, for example, diesel engines, gasoline engines, or natural gas engines employ turbochargers to deliver compressed air for combustion in the engine. A turbocharger compresses air flowing into the engine, helping to force more air into combustion chambers of the engine. The increased supply of air allows more fuel to be burnt in the combustion chambers resulting in increased power output from the engine.
A typical turbocharger includes a housing, a shaft, a turbine wheel attached to one end of the shaft, and a compressor impeller connected to the other end of the shaft. Exhaust from the engine expands over the turbine wheel and rotates the turbine wheel. The turbine wheel, in turn, rotates the compressor impeller via the shaft. The compressor impeller receives cool air from the ambient and forces compressed air into the combustion chambers of the engine.
The exhaust from the engine is significantly hotter than the ambient air. As a result, the turbine portion of the turbocharger can undergo a higher degree of thermal expansion compared to the compressor portion and/or other relatively cooler components of the turbocharger. The differential thermal expansion causes relative motion between the attached components of the turbocharger, making it difficult to keep the components securely fastened to each other during operation of the turbocharger. The differential expansion can also cause the turbine wheel to come into contact with the turbocharger housing, causing damage to the turbine wheel and the turbocharger housing.
One attempt to address some of the problems described above is disclosed in U.S. Pat. No. 6,371,238 of Svihla issued on Apr. 16, 2002 (“the '238 patent”). In particular, the '238 patent discloses that a turbine end of the exhaust duct and a turbine inlet scroll are supported by a support structure that includes a pair of laterally spaced support legs having feet which are fixed to a base. The '238 patent further discloses that the legs extend upward on opposite sides of the rotational axis of the turbocharger to connect with the exhaust duct, or a duct support, at points above the axis of the rotor and associated ducting. Further, the '238 patent discloses that preferably, the points at which the legs are connected with the exhaust duct support are at selected points above the axis where vertical expansion of the exhaust housing between the axis and the connection with the legs approximately equals linear expansion of the legs.
Although the support structure disclosed in the '238 patent appears to account for thermal expansion, the disclosed support structure may still be less than optimal. In particular, making support legs separate from the duct support may add complexity and cost to the manufacturing process. Further, the legs of the support structure disclosed in the '238 patent appear to align with the bolting pattern on the exhaust duct. Thus, manufacture of the support legs may require complicated casting patterns, which may require cores to account for the bolting pattern, making the casting process more expensive. In addition, because the legs of the support structure of the '238 patent directly attach to the duct support, the disclosed support structure may not allow for differential thermal expansion between the connected components.
The turbine housing support structure of the present disclosure solves one or more of the problems set forth above and/or other problems of the prior art.